Cells, genes con­tinue to func­tion af­ter death

Iran Daily - - Science & Technology -

Even af­ter you die, your body’s cells will con­tinue to func­tion. Ac­cord­ing to a new study pub­lished in the jour­nal Na­ture Com­mu­ni­ca­tions, the body’s cells host post-mortem ge­netic ex­pres­sion for 24 to 48 hours.

All of the bi­o­log­i­cal func­tions that make life pos­si­ble are pow­ered by our genes — and specif­i­cally, the ex­pres­sion of those genes, UPI re­ported.

Re­cently, an in­ter­na­tional team of sci­en­tists ob­served ge­netic ac­tiv­ity in post-mortem cells.

Genes and ge­netic ac­tiv­ity are de­fined by two types of code, DNA and RNA.

DNA are the in­struc­tions, while RNA acts as the in­ter­preter. RNA ‘ex­presses’ the DNA, read­ing the code and trans­lat­ing it into ac­tion — or bi­o­log­i­cal func­tions.

When hu­mans suf­fer dis­eases, it is of­ten caused by a dis­rup­tion of the ge­netic trans­la­tion and ex­pres­sion process.

While RNA can di­rectly con­trol some cel­lu­lar pro­cesses, it also pro­vides the coded in­struc­tions for the pro­teins car­ry­ing out a va­ri­ety of cel­lu­lar func­tions.

Study­ing these coded in­struc­tions, called tran­scrip­tomics, is the pri­mary way sci­en­tists gain in­sights into the cel­lu­lar fac­to­ries that make life pos­si­ble.

To bet­ter un­der­stand how ge­netic ac­tiv­ity em­pow­ers cel­lu­lar func­tions, sci­en­tists need to study cel­lu­lar sam­ples.

Tis­sues and or­gans re­moved af­ter death of­fer an abun­dance of cel­lu­lar sam­ples, but un­til now, sci­en­tists weren’t sure whether post-mortem cells could of­fer an ac­cu­rate amal­gam for the cells of a liv­ing body.

Roderic Guigó, a pro­fes­sor of com­pu­ta­tional bi­ol­ogy at the Barcelona In­sti­tute for Sci­ence and Tech­nol­ogy, said, “You would ex­pect that with the death of the in­di­vid­ual, there would be a de­cay in the ac­tiv­ity of the genes.”

But when Guigó and his col­leagues com­pared ge­netic ac­tiv­ity in­side cells from post-mortem tis­sue and or­gan sam­ples to the ge­netic ac­tiv­ity of blood drawn from liv­ing hu­mans, they found ge­netic ex­pres­sion con­tin­ues af­ter death.

While post-death RNA lev­els don’t di­min­ish, the types of ge­netic ex­pres­sion do change af­ter death. Some types of RNA tran­scrip­tion ac­tu­ally in­creases af­ter death, the re­search showed.

Guigó said, “There is a re­ac­tion by the cells to the death of the in­di­vid­ual.

“We see some path­ways, some genes, that are ac­ti­vated and this means that some­time af­ter death there is still some ac­tiv­ity at the level of tran­scrip­tion.”

The new re­search sup­ported the find­ings of other sci­en­tists who’ve shown the med­i­cal def­i­ni­tion of death isn’t fi­nal, and that even brain cells can con­tinue to func­tion in some ca­pac­ity af­ter the heart has stopped pump­ing.

Some stud­ies have even sug­gested hu­man con­scious­ness can con­tinue on af­ter the med­i­cal def­i­ni­tion of death — de­fined by the loss of heart and res­pi­ra­tory func­tion.

In ad­di­tion to of­fer­ing a bet­ter over­all un­der­stand­ing of our cells’ ge­netic func­tion­al­ity, the lat­est re­search could also in­spire new foren­sic tests, al­low­ing sci­en­tists to more ac­cu­rately pre­dict the time of death.

Guigó said, “We con­clude there is a sig­na­ture or a fin­ger­print in the pat­tern of gene ex­pres­sion af­ter death that could even­tu­ally be used in foren­sic sci­ence, but we don’t pre­tend we have now a method that can be used in the field.”

Cel­lu­lar DNA con­tin­ues to be ex­pressed via RNA af­ter death, new re­search found. UPI

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